High-frequency heatable plastics

ABSTRACT

Olefin polymers which are unsuited, or ill-suited, for heating, sealing, or bonding by the action of high-frequency electromagnetic radiation, especially microwave radiation, are rendered heatable by such radiation by incorporating carbon monoxide, as a comonomer, into the polymer structure. Novel adhesives comprising terpolymers of ethylene/carbon monoxide/acids are disclosed, where the acid moiety of the terpolymer is at least one carboxylic acid which is polymerizable through carbon-to-carbon unsaturation, and salts thereof.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of our co-pending applicationSer. No. 531,110 filed Sept. 12, 1983.

BACKGROUND OF THE INVENTION

The use of high-frequency electromagnetic energy as a means of heatingpolymers is an advancing art which finds application in many fields,especially in fields in which conventional conductive, convective, orradiant heat energy is either not suitable, not practical, or notpossible. For instance, sealing of a polymer to itself or to some othersubstrate can be (if the composition of the polymer is appropriate) animportant commercial technique in producing a desired end-product.

There are some polymers which are not suitable, or at least notwell-suited, for high-frequency heating operations. In such ill-suitedpolymers high-frequency heating either does not occur, or if it occursit does so only after inefficiently prolonged periods of treatment time.In production assembly lines, e.g., a quick heat-seal operation isgenerally preferred over a prolonged heat-seal operation.

Among the polymers which are ill-suited for high-frequency heating areolefin polymers, e.g., polymers and copolymers of ethylene, propylene,styrene or other α-olefinically unsaturated hydrocarbons having about 2to about 10 carbon atoms. Some of these olefin polymers may containpolar groups, or polarizable groups, due to the incorporation thereinof, e.g., acrylic (or methacrylic) acids or their alkyl esters ascomonomers with the olefins, and these groups may, at high levels ofincorporation tend to impart a modicum of high-frequency heatability tothe polymer, but the efficacy is generally so slight that it isinfeasible on a commercial basis. Some polymers having polar groups,e.g. chlorinated P.E., ethylene/vinyl acetate copolymer, PVC,polyvinylidene chloride, and polyamide, are heatable under the influenceof certain frequencies of electromagnetic radiation.

Polyethylene is particularly known in the art to be substantiallyunsuitable for high-frequency heating unless sensitizers are added tothe polymer; this is true regardless of whether it is linear orbranched, or of whether it is low, medium, or high density (see, e.g.,U.S. Pat. No. 3,336,173; U.S. Pat. No. 3,640,913; and U.S. Pat. No.3,810,799).

It is an object of the present invention to provide ways and means forimparting improved high-frequency heatability to those olefin polymersand copolymers which ordinarily are found to be ill-suited for suchheating operations.

SUMMARY OF THE INVENTION

High-frequency heatability (e.g., for sealing, bonding, extrusion,molding, melting, and the like) is imparted to olefin polymers bypolymerizing carbon monoxide into the polymer structure, thus providingnovel capabilities for high-frequency heating of polymers which,otherwise, are unsuited, or at least ill-suited, for high-frequencyheating operations. Novel high-frequency heated articles are preparedand novel high-frequency heating operations are provided as a result ofthe carbon monoxide inclusion in the polymer. Novel terpolymers ofethylene/CO/carboxylic acids, such as acrylic acid, and salts thereof,are prepared which, in addition to being heatable by high-frequencyelectromagnetic energy, are found to have better adhesion to varioussubstrates than copolymers of ethylene/carboxylic acids and saltsthereof.

DETAILED DESCRIPTIONS

The preparation of olefin polymers, copolymers, and terpolymers is wellknown and the methods and techniques are well known to practitioners ofthe relevent polymer art. For the most part, the olefin copolymers andterpolymers of interest in this present disclosure are prepared by thewell known high pressure, high temperature, free-radical initiated,polymerization method such as the historically-popular ICI process orsuch as disclosed in U.S. Pat. No. 2,497,323. However, thosepolymerization processes which employ certain of the coordinationcatalysts or metal catalysts (e.g., the well-known Ziegler-type,Natta-type, or Phillips-type) may be used by selecting a catalyst (suchas in U.S. Pat. No. 3,083,184) which is not easily poisoned ordeactivated by carbon monoxide, or other oxygen-containing monomer,which is generally highly reactive with many metal-carbon bonds.

Olefin polymers within the purview of this invention, and which arerendered heatable (by highfrequency electromagnetic radiation) byincorporating carbon monoxide groups into the polymer chain, arepolymers formed by polymerizing monomers having ethylenic (olefinic)unsaturation. A sole olefin or a plurality of olefins may be used alongwith the carbon monoxide in preparing the polymers. Preferably theolefin monomer is ethylene (sometimes including a small proportion of aC₃ -C₈ aliphatic olefin for property modification). The olefin monomercan also include an unsaturated organic acid having 3 to 8 carbon atoms,such as acrylic acid, methacrylic acid, 1-butenoic acid, and the like;alkyl esters or metal salts of these acids may also be used, such asethyl acrylate, methyl methacrylate, 2-ethyl hexyl acrylate, sodiumacrylate, potassium methacrylate, and the like. HydrogenatedCO-containing olefin polymers (which creates C--OH groups along thepolymer chain) are included here, such as hydrogenated ethylene/carbonmonoxide copolymers. U.S. Pat. No. 2,495,292 discloses methods ofhydrogenating such CO groups in a polymer chain.

It has been known for many years that olefins, e.g. ethylene, and carbonmonoxide, can be copolymerized or terpolymerized.

The following listed patents are believed to be representative of theart pertaining to interpolymers of carbon monoxide and monoolefins: U.S.Pat. No. 2,495,292; U.S. Pat. No. 2,495,286; U.S. Pat. No. 2,497,323;U.S. Pat. No. 2,641,590; U.S. Pat. No. 3,083,184; U.S. Pat. No.3,248,359; U.S. Pat. No. 3,530,109; U.S. Pat. No. 3,676,401; U.S. Pat.No. 3,689,460; U.S. Pat. No. 3,694,412; U.S. Pat. No. 3,780,140; U.S.Pat. No. 3,835,123; U.S. Pat. No. 3,929,727; U.S. Pat. No. 3,948,832;U.S. Pat. No. 3,948,873; U.S. Pat. No. 3,948,850; U.S. Pat. No.3,968,082; U.S. Pat. No. 3,984,388; U.S. Pat. No. 4,024,104; U.S. Pat.No. 4,024,325; U.S. Pat. No. 4,024,326; U.S. Pat. No. 4,139,522; U.S.Pat. No. 4,143,096; and U.S. Pat. No. 4,304,887.

It is also known that there are additives (sensitizers) which can beblended into a polymer, e.g. polyethylene, to render it heatable byelectromagnetic high-frequency energy, such as talc, ZnCl₂, carbonblack, nylon, iron oxide, and others. Such additives, however, usuallyhave a pronounced visual, physical, or chemical effect which, in someapplications, is desirably avoided. Furthermore, when using additives assensitizers one is faced with having to obtain a uniform distribution ofthe sensitizers in order to avoid "hot-spots" which can give irregularresults and may even damage the polymer.

It is within the purview of the present inventive concept to createhigh-frequency sensitizer groups along the polymer chain in polymerswhich otherwise would be ill-suited for high-frequency heating. In thisinvention one does not encounter untoward visual effects in the polymeras a result of the sensitizer. Even in the present embodiments wherein apolymer of the present invention is blended with polymer (e.g., as a"masterbatch") in order to sensitize the whole, the polymers aregenerally compatible to an extent at which little or no visual effectsare encountered. Thus, clear films of olefin polymers can be prepared,in accordance with the present invention, which are readily heat-sealedusing high-frequency energy. It is especially of importance that thepresent invention provides polymers which are heatable by the action ofmicrowave (MW) energy, a particular portion of the high-frequency energyrange, thereby helping to fill a need in the industry where there is asparsity of polymers which are suitable. The amount of CO groups in theethylene interpolymers should be in the range of about 0.1 to about 50%by weight, preferably about 1 to about 40% by weight, most preferablyabout 5 to about 30% by weight.

As used herein "high-frequency sealability" refers to the bonding of thesealable polymer to a portion of itself or to another material usingelectromagnetic energy frequencies of 0.1-30,000 MHz. This includesradio-frequency (RF) heating and microwave (MW) heating incontradistinction to conventional heat sealing. The high-frequency rangeis generally taken to include electromagnetic waves over a broadfrequency range (0.1 to 30,000 MHz) and covers the ultrasonic frequencyrange (18 KHz-1000 KHz), the radio frequency (RF) range (1 MHz-300 MHz),and the microwave (MW) frequency range (300 MHz-10,000 MHz). The RF andMW ranges are of particular interest here, with special interest in theMW range due to the increasing use of MW as a processing device.

Uses for this technology (polymer or blends) includes packagingapplications where high speed seals are required, e.g., high-frequencyactivated adhesive films; extrusion coatings; moldings; hot melts inuses such as aseptic packaging, retort pouches, sandwich bags;lamination of foam, fabric, or film layers; powder moldings, and thelike. Furthermore, the present invention provides polymers suitable foruse in RF extruders, including continuous extruders or batch extruders.Wire and cable coatings can be applied in a continuous RF-extruder bythe present invention.

In one aspect, this invention relates to an improved method of renderinga polymer which is not heatable or sealable utilizing high-frequency(0.1-30,000 MHz) electromagnetic radiation (HF) (e.g., polyethylene,polypropylene, polystyrene, etc.) HF-sealable by either incorporation ofcarbon monoxide by copolymerization or by blending or grafting a carbonmonoxide copolymer or terpolymer into the polymer matrix. Hydrogenatedforms of the above can also be used. In addition, ethylene/carbonmonoxide copolymer (ECO) and interpolymers containing CO can be used formicrowave sealing applications (i.e., microwave sealable plastic bags,toothpaste tube sealing, shampoo tube sealing, other microwave sealablecontainers, valve bag sealing, etc.). We have unexpectedly found thatECO copolymers and interpolymers convert high-frequency electromagneticradiation into heat for sealing, welding or fusing over a broadfrequency range (0.1-30,000 MHz). Typically, ethylene copolymers may beheatable to some extent at low RF frequencies of 1-50 MHz (radiofrequency range is typically considered to be from 1-300 MHz; microwavefrequency range is 300-30,000 MHz) such as ethylene/vinyl acetatecopolymer (EVA), but none have been found which efficiently heat at thehigher frequencies. Other examples of polymers heatable at lowfrequencies, but which do not efficiently heat at the higher frequenciesare polyvinyl chloride (PVC), polyvinylidene chloride, chlorinatedpolyethylene (CPE), and Nylon 6.

The advantages of sealing polymers with high-frequency electromagneticwaves include faster and more efficient sealing, sealing through poorheatconductors, e.g., paper or cardboard exteriors, stronger seals orbonds, improved economics based on efficient use of energy input, theability to seal, bond, or laminate larger surface areas, sealing ofthicker or more complex film laminates and specific sealing.

The general heating rate for the interaction of an electromagnetic wavecan be used to determine sealing rates utilizing the following equation:

    G=13.3×10.sup.-14 fF.sup.2 (E'tan δ)           (1)

where G is the heating rate in cal/cm³ ·sec, f is the frequency in Hz ofthe electromagnetic wave, F² is the field strength or power in volts/cm,E' is the dielectric constant of the polymer and tan δ is the dielectricloss tangent (measure of the heating property of the material whenexposed to HF electromagnetic waves). Thus, in general (since tan δvaries with frequency) the higher the frequency the higher the heatingrate or the faster the sealing ability of the material. The carbonmonoxide (CO) containing interpolymers can be sealed or heated over abroad frequency range which allows one to have the option of usingmicrowave frequencies for optimum speed in heating or sealing. Thisfeature (heating or sealing over such a broad frequency) appears to beunique to these interpolymers or copolymers containing CO.

There are also advantages of CO copolymers or interpolymers over otherpolymers (e.g., PVC, PVCl₂, CPE, EVA), that are sealable using radiofrequency sealing methods which include, for example:

1. ECO is like conventional low density polyethylenes in physicalproperties and film appearance, i.e., higher melting point, low filmblockage, easy processability, can be used for film, extrusion coatingand molding resin. Furthermore, the need for plasticizers is obviated.

2. CO can be copolymerized with ethylene and vinyl acetate to produce aCO-modified EVA polymer to render it more sealable and broadens thesealing frequency range. CO can also be copolymerized into an EAA orEMAA polymer allowing an EAA-like or EMAA-like terpolymer to be RF andmicrowave sealable (EAA and EMAA are not RF or microwave sealable). Thisincludes the metal salts or "ionomer-type" embodiments of thesepolymers.

3. CO containing copolymers or interpolymers have higher dielectricconstants than EVA copolymers, allowing higher field strengths to beused without the fear of arcing.

EXAMPLE 1

The following Table I shows the time required to melt a polymer in amicrowave oven (Sears Microclassic microwave oven) at maximum power(brought 275 ml of water to boil in 2.48 minutes).

                  TABLE I                                                         ______________________________________                                                                   Melt Time                                          Resin*            MI***    (sec)**                                            ______________________________________                                        ECO                                                                           10% CO            1        37                                                 10% CO            10       35                                                  5% AA; 10% CO    10       75                                                  5% AA; 10% CO    3.5      85                                                  5% AA;  5% CO    3        90                                                  1% CO            1        90                                                 EVA (14% VA)      wax      >10 min                                            EAA (12% AA)      wax      >10 min                                            Oxidized (PE)     wax      >10 min                                            E/vinyl alcohol   --       42                                                 EVA/CO (20% CO)   --       25                                                 EVA                                                                           28% VA            3.5      >10 min                                            18% VA            3.0      >10 min                                            EAA                                                                           20% AA            300      >10 min                                            30% AA            1250     >10 min                                            HDPE (0.965 dens.)                                                                               .8      >10 min                                            LDPE (0.918 dens.)                                                                              6        >10 min                                            LLDPE (0.918 dens.)                                                                             6        >10 min                                            6 resin (dried)   --       >10 min                                            Saran ® B-200 polymer                                                                       --       >10 min                                            Chlorinated P.E.  --       >10 min                                            ______________________________________                                         *Samples were 2" discs of 60 mil thickness, positioned on a nonRF             sensitive polycarbonate sheet.                                                **If no melting was evident in 10 minutes, the test was stopped and           reported as >10 min.                                                          ***MI is melt index in accordance with ASTM D1238, reporting the melt flo     rate of extrusion in grams per 10 minutes.                                    ® Registered tradenames                                              

As can be seen from Table I, only ethylene/vinyl alcohol polymer andethylene interpolymers containing carbon monoxide melted in themicrowave oven (2450 MHz).

EXAMPLE 2

In order to determine the RF-sealability of carbon monoxide containingcopolymers, a Callanan 11/2 KW high-frequency electronic generatorequipped with a 3/32"×12" brass sealing electrode and operating over afrequency range of 20-40 MHz (RF) was utilized in the following sealingexperiment. Samples of 3 mil blown film of the copolymers shown in TableII were attempted to be sealed using the above RF sealer utilizingvarious dwell settings (sealing time) and power settings. The seals wereexamined and a seal was considered to have been made when the two sheetsof material could not be separated at the seal point without tearingeither piece of film. Table II also shows the improvement in minimumsealing time and resistance to arcing of CO containing copolymers incomparison to EVA copolymers. The melt flow rate, showing the rate ofextrusion in g/10 min., according to ASTM D-1238, is reported as meltindex (MI) in Table II.

                  TABLE II                                                        ______________________________________                                        RADIO FREQUENCY SEALABILITY                                                               Power     Dwell Time                                              Resin       Setting   sec.       Sealability                                  ______________________________________                                        EVA         90        3          No                                           (9.3% VA, 2 MI)                                                                           100       3          No                                                       100       4          Arc*                                         EVA         10        1          No                                           (18% VA, 2.5 MI)                                                                          40        2          No                                                       70        2          Yes                                                      60        2          Yes                                                      70        1          No                                                       80        1          Yes                                                      90        2          Arc                                          EVA         60        2          No                                           (12.0% VA, 2.5 MI)                                                                        70        2          No                                                       80        2          No                                                       90        2          Yes                                                      100       1          Arc                                          EVA         30        2          Yes                                          (25% VA, 2 MI)                                                                            20        2          No                                                       60        1          Yes                                                      60        .5         No                                                       70        .5         No                                                       80        .5         Arc                                          EVA         40        2          Yes                                          (28% VA, 3.0 MI)                                                                          20        1          Yes                                                      70        .5         Yes                                                      80        .25        Arc                                                      80        .5         Arc                                          ECO         50        2          No                                           (10% CO, 1 MI)                                                                            60        2          No                                                       70        2          Yes                                                      100       1          Yes                                                      90        1          Yes                                                      80        1          No                                                       100       .5         Yes                                                      90        .5         No                                           E/AA/CO     70        2          Yes                                          (5% AA, 10% CO,                                                                           60        2          Yes                                          3.5 MI)     50        2          Yes                                                      70        1          Yes                                                      60        1          Yes                                                      70        .5         Yes                                                      60        .5         No                                                       80        .25        No                                                       90        .25        Yes                                          E/AA/CO     70        .5         Yes                                          (5% AA, 10% CO,                                                                           80        .5         Yes                                          10 MI)      80        .25        No                                                       90        .25        Yes                                          ______________________________________                                         *Arc results in a hole burned through the film.                          

Within the purview of the present invention, useful articles areprepared which utilize the high-frequency electromagnetic radiationheatability and sealability of the above described CO containing olefinpolymers. Layers or plies of these polymers are used as a means forsealing or bonding materials which are not, themselves, efficientlysuitable for high-frequency electromagnetic radiation sealing orbonding. Various substrates, including particles, films, sheets, blocks.rods, spheres, and the like can be coated, at least in the area desiredto be bonded, with these subject polymers and then sealed or bondedtogether using high-frequency electromagnetic radiation, especiallythose frequencies in the microwave range. These polymers, in the form ofpowders or particles, may be extruded into useful shapes, or as coatingsonto other materials (e.g. wire and cable coatings), usinghigh-frequency electromagnetic radiation as the heating means.

Novel adhesives comprising terpolymers of ethylene/carbonmonoxide/carboxylic acid are prepared as embodiments in accordance withthe present invention. The carboxylic acid moiety of the terpolymer maybe any of the unsaturated carboxylic acid which are polymerizablethrough the double-bond, such as acrylic acid, methacrylic acid,crotonic acid, 1-butenoic acid, and the like, especially acrylic acid ormethacrylic acid, most especially acrylic acid, including salts of theseacids, such as metal salts, especially Na or K salts, commonly known as"ionomer" salts. The preparation of these E/CO/acid terpolymers may bedone in the same manner as the E/acid copolymers as disclosed in U.S.Pat. No. 3,520,861 and U.S. Pat. No. 4,351,931. These patents disclosethe use of a high pressure stirred autoclave reactor, using afree-radical initiator, to prepare uniform, random ethylene/carboxylicacid copolymers. Whereas these terpolymers can also be made by graftingtechniques, by block polymerization techniques, in batch reactors, or inlong tube reactors, it is preferred that the above disclosed stirredautoclave reactors be used whereby substantially uniform, randomterpolymers are made.

Even though E/AA copolymers are generally regarded as having goodadhesive properties with many substrates, as compared to polyethylene,there are some substrates where improved adhesion is desirable. Notableamong these substrates, where improved adhesion is desirable, arepolyamides (e.g. nylons), polyolefins (e.g. LDPE, HDPE, LLDPE, PP, OPP,polyisoprene), fluoropolymers (e.g. PTFE), polyethylene terephthalate(PET), metals (e.g. steel and aluminum foil), some paper-type products(e.g. glassine, kraft paper, etc.), cured epoxy resins, ethylene/vinylalcohol copolymers, cured novolac resins, polyurethanes, polycarbonates,chloropolymers (e.g. polychloroprene, PVC, polyvinylidene), andinorganic substrates (e.g. glass and porcelain).

Conversely, whereas ECO copolymers exhibit a modicum of heat-activatedor heat-induced adhesive properties to some substrates, it has beendetermined that the present E/CO/acid terpolymers exhibit greateradhesiveness in such instances, especially to such substrates as SARANpolymer and polycarbonate (where ECO has some adhesiveness) and toethylene/vinyl alcohol copolymers, nylon, and aluminum (where ECOexhibits little or no adhesiveness).

The adhesive properties of these E/CO/acid terpolymers may be utilizedby any convenient method, such as by hot-melt application, bypost-heating of the adhesive in-situ on the substrate, by application ofthe adhesive in a carrier, such as in a solvent or as a dispersion in anaqueous carrier or in a non-solvent. The adhesive may be used in joiningsubstrates of similar or dissimilar materials. As mentionedhereinbefore, these terpolymers are also suitable for use as films or asother materials and have the beneficial property of being high-frequencyheatable, especially at those frequencies which are in, or near, themicrowave range.

These E/CO/acid terpolymers are quite similar in optics and physicalproperties to EAA copolymers made by the same process. Insofar as thesenovel adhesive terpolymers are concerned, the ranges of the comonomeringredients are as follows:

    ______________________________________                                        Weight % of Terpolymer                                                                                         Most                                         Monomer      Operable   Preferred                                                                              Preferred                                    ______________________________________                                        Ethylene     20-98      40-98    60-96                                        Carbon Monoxide                                                                            1-40       1-30     2-20                                         Carboxylic Acid                                                                            1-40       1-30     2-20                                         ______________________________________                                    

The melt index (M.I.), also called melt flow rate, as measured inaccordance with ASTM D-1238, is preferably in the range of about 0.5 toabout 2500, most preferably in the range of about 1 to about 60, evenmore preferably in the range of about 1 to about 20.

These E/CO/acid terpolymers are thermoplastic and can be thermoformedinto films, sheets, tubes, or other articles. Powders of theseterpolymers can be compression molded into sintered forms or the powderscan be applied to the surface of a substrate where it can beheat-plastified to provide an adhesive layer or coating on the substrateor between two substrates. A film, strip, or sheet of these terpolymerscan be placed between two substrates and heat-plastified to serve as anadhesive or laminate layer to hold the substrates together.

The following examples illustrate certain embodiments of the E/CO/acidterpolymers, compared with other polymers, but the invention is notlimited to the specific embodiments shown.

EXAMPLE 3

The examples shown in Table III below are produced by compressionmolding at pressures and temperatures conducive to heat fusion. Theresin samples to be tested for adhesion are first compression moldedinto 20 mil plaques and then laminated to the substrate (a film orplaque) to test for adhesion to the substrate. The adhesive ofethylene/carbon monoxide/acrylic acid terpolymers, E/CO/AA, is shown incomparision to low density polyethylene, LDPE; ethylene/acrylic acidcopolymer; E/AA; ethylene/vinylacetate copolymer, E/VA; ethylene/carbonmonoxide copolymer, E/CO; and ethylene/ carbon monoxide/vinyl acetateterpolymer, E/CO/VA. The good adhesiveness obtainable with E/CO/AAterpolymers to the various substrates is evident, especially with nylon(a polyamide) and with polycarbonate which generally do not form strongbonds with most heat-plastified adhesives.

                                      TABLE III                                   __________________________________________________________________________    COMPRESSION MOLDED ADHESION VALUES (lbs/in)                                               PERCENT                                                                       COMONOMER                                                                     WITH ETHYLENE SUBSTRATE                                           ADHESIVE    AA CO VA  MI  A.sup.1                                                                             B.sup.2                                                                            Nylon.sup.3                                                                         Aluminum.sup.4                                                                      EVAL.sup.5                                                                          Polycarbonate.sup.6    __________________________________________________________________________    LDPE        -- -- --  --  .01     .01                                                                               .01    .05  .01  .01                    E/AA Copolymer                                                                            6.2                                                                              -- --  3.02                                                                              .01     .02                                                                              2.4   18.1   .50  .05                    E/AA Copolymer                                                                            9.8                                                                              -- --  9.6 .01     .01                                                                              3.8   29.2   .70  .08                    E/AA Copolymer                                                                            9.0                                                                              -- --  3.6 .01     .01                                                                              4.2   27.4   .50  .08                    E/VA Copolymer                                                                            -- -- 28.5                                                                              5.8 7.5    6.3 5.4    2.1  3.1   .08                    E/VA Copolymer                                                                            -- --  6.5                                                                              1.11                                                                              .04     .10                                                                               6.44  8.9  6.8   .05                    E/CO/AA Terpolymer                                                                        5.0                                                                               5.0                                                                             --  56.1                                                                              >10.47                                                                              >2.39                                                                               1.83 18.0  3.1   7.5                    E/CO/AA Terpolymer                                                                        5.0                                                                              10.0                                                                             --  4.3 11.8  >1.89                                                                               9.88 16.0  7.5   >10.4                  E/CO/AA Terpolymer                                                                        5.0                                                                              10.0                                                                             --  18.7                                                                              9.0   >4.2 >23.2 22.5  7.9   >10.4                  E/CO Copolymer                                                                            0  10.0                                                                             --  7   9.6   >2.4  .5    .4    .2   >7.8                   E/CO Copolymer                                                                            0  10.0                                                                             --  8.2 10.3  >4.1  .1    .8    .5   >8.2                   E/CO/AA Terpolymer                                                                        10.0                                                                              5.0                                                                             --  4.1 7.1    1.5 >24.2 24.9  6.9   DNR                    E/CO/AA Terpolymer                                                                        -- 10.0                                                                             10.0                                                                              35.2                                                                              8.2    6.1 8.8    2.0   1.33 DNR                    __________________________________________________________________________     > indicates cohesive failure strength of film substrate                       A.sup.1 6mil SARAN PVDC film                                                  A.sup.2 2mil SARAN PVDC film                                                  .sup.3 Nylon6 film                                                            .sup.4 Aluminum                                                               .sup.5 ethylene/vinyl alcohol copolymer, molded 20mil plaque                  .sup.6 2mil polycarbonate cast film                                      

EXAMPLE 4

In order to compare an ethylene/carbon monoxide copolymer (10% CO byweight, 18.7 M.I.) with an ethylene/carbon monoxide/acrylic acidterpolymer (10% CO and 5% AA by weight, 12.8 M.I.), a 2-mil thickcoating of each is extrusion-coated onto various substrates and adhesion(lb./in.) is measured. In Table IV below, Sample A is the E/CO copolymerand is extrusion-coated at about 300° C.; Sample B is the E/CO/AAterpolymer and is extrusion-coated at about 290° C.; PVDC meanspolyvinylidene chloride; EVAL means ethylene/vinyl alcohol copolymer;LLDPE means linear low density polyethylene; LDPE means low densitypolyethylene; PET means polyethylene terephthalate; OPP means orientedpolypropylene.

                                      TABLE IV                                    __________________________________________________________________________    SAMPLE                                                                              PDVC                                                                              PET                                                                              POLYAMIDE                                                                             OPP ALUMINUM                                                                              LDPE                                                                              LLDPE                                    __________________________________________________________________________    A     >5* 0.5                                                                              0.32    <0.05                                                                             0.14    0.3 0.07                                     B     >5* 1.6                                                                              2.44     0.05                                                                             2.5     0.5 0.5                                      __________________________________________________________________________     *All > samples resulted in film failure, not adhesive failure. The above      illustrates the superior adhesiveness of E/CO/AA terepolymers as compared     to E/CO copolymers.                                                      

EXAMPLE 5

The packaging industry utilizes a number of barrier resins, such as inTable V below, and the E/CO/acid terpolymers are found to make goodadhesives for making laminates which contain one or more barrier layers.

                  TABLE V                                                         ______________________________________                                        Oxygen Barrier Resistance                                                     Nominal Value                                                                            Polymer                                                            ______________________________________                                        0.03-0.30  ethylene/vinyl alcohol copolymers; EVAL                            0.05-0.20  polymers or copolymers based in vinyl                                         chloride and/or vinylidene chloride                                           monomers; SARAN                                                     2         polyvinyl chloride, PVC                                            80         plasticized PVC                                                     4         PET, polyethylene terephthalate                                    10         nylon, polyamide                                                   125        HDPE, high density polyethylene                                    ______________________________________                                    

EXAMPLE 6

It has been determined that E/CO/acid terpolymers are useful asheat-plastified adhesives between layers of similar plastics or resins,layers of dissimilar plastics or resins, and/or between layers ofplastics or resins and completely different substrates, such as paper,cloth, metal, glass, vitreous material, wood, leather. These terpolymersare also useful as heatplastified adhesives between layers of materials,neither layer being plastic or resin, such as the materials namedimmediately above.

We claim:
 1. A composition of matter comprising a terpolymer ofethylene/carbon monoxide/acid where the said acid comprises acrylic acidor methacrylic acid,wherein the ethylene comprises an amount in therange of 20% to 98% by weight, the carbon monoxide comprises an amountin the range of 1% to 40% by weight, and the acid comprises 1% to 40% byweight of the total weight, said terpolymer being further characterizedas being a substantially uniform, random terpolymer having a melt flowrate, as measured by ASTM D-1238, in the range of about 0.5 to about2500 g/10 minutes.
 2. The terpolymer of claim 1 wherein the acid groupsare in the form of a metal salt.
 3. The terpolymer of claim 1 whereinthe acid groups are in the form of a metal salt, where the said metalcomprises an alkali metal.
 4. The terpolymer of claim 1 wherein the acidgorups are in the form of a metal salt, where the said metal comprisesat least one of Li, Na, K, or Rb.
 5. The terpolymer of claim 1 whereinthe acid comprises acrylic acid.
 6. The terpolymer of claim 1 whereinthe acid comprises methacrylic acid.
 7. The terpolymer of claim 1 whenin the form of a layer adhered to at least one substrate.
 8. Theterpolymer of claim 1 when in the form of a layer adhered to at leastone plastic or resin substrate.
 9. The terpolymer of claim 1 when in theform of a layer adhered to at least one substrate of the groupcomprising paper, cloth, leather, metal, glass, vitreous material, andwood.
 10. The terpolymer of claim 1 when in the form of an adhesivebetween substrates, wherein the substrates are of similar material. 11.The terpolymer of claim 1 when in the form of an adhesive betweensubstrates, wherein the substrates are of dissimilar materials.
 12. Theterpolymer of claim 1 when in the form of a layer on a substrate,wherein said substrate has good oxygen barrier properties.
 13. Theterpolymer of claim 1 when in the form of a layer on at least onesubstrate of the group comprising polyvinyl chloride, polyvinylidenechloride, polyethylene terephthalate, polyamide, polypropylene, orientedpolypropylene, ethylene/vinyl alcohol copolymer, ethylene/vinyl acetatecopolymer, polycarbonate, low density polyethylene, high densitypolyethylene, and linear low density polyethylene.
 14. The terpolymer ofclaim 1 wherein the ethylene comprises an amount in the range of about40% to about 98% by weight, the carbon monoxide comprises an amount inthe range of about 1% to about 30% by weight, and the acid comprisesabout 1% to about 30% by weight of the total weight, and the terpolymerhas a melt flow rate in the range of about 1 to about 60 g/10 minutes.15. The terpolymer of claim 1 wherein the ethylene comprises an amountin the range of about 60% to about 96% by weight, the carbon monoxidecomprises an amount in the range of about 2% to about 20% by weight, andthe acid comprises about 2% to about 20% by weight of the total weight,and the terpolymer has a melt flow rate in the range of about 1 to about20 g/10 minutes.